Assessment of endophytic bacterial diversity in rose by high-throughput sequencing analysis.

The endophytic bacterial diversity of rose was analyzed by high-throughput sequencing of 16S rDNA and functional prediction of the bacterial community. The number of bacterial sequence reads obtained from 18 rose samples ranged from 63,951 to 114,833, and reads were allocated to 1982 OTUs based on sequences of the V3-V4 region. The highest Shannon Index was found in Luogang rose (1.93), while the lowest was found in Grasse rose (0.35). The bacterial sequence reads were grouped into three different phyla: Firmicutes, Proteobacteria, and Actinobacteria. At the genus level, Bacillus and Staphylococcus had the highest abundance across all 18 samples; Bacillus was particularly abundant in Daguo rose (99.09%), Rosa damascena (99.65%), and Fenghua rose (99.58%). Unclassified OTUs were also found in all samples. PICRUSt gene prediction revealed that each endophyte sample contained multiple KEGG functional modules related to human metabolism and health. A high abundance of functional genes were involved in (1) Amino Acid Metabolism, (2) Carbohydrate Metabolism, (3) Cellular Processes and Signaling, (4) Energy Metabolism, and (5) Membrane Transport, indicating that the endophytic community comprised a wide variety of microorganisms and genes that could be used for further studies. The rose endophytic bacterial community is rich in diversity; community composition varies among roses and contains functional information related to human health.

The complete mitochondrial DNA sequence of Yimeng scorpion (Mesobuthus martensii).

Yimeng scorpion is a specific geographical indication breed of Yimeng Mountain area in China. The complete mitochondrial genome sequence of Yimeng scorpion was determined for the first time (Accession number MN597087). It is mitochondrial genome (14,840 bp) contains 13 protein-coding genes, 21tRNA genes, 2 ribosomal RNA genes and one large non-coding region (a possible control region). Moreover, tRNA-ASP-loss was observed from the Yimeng scorpion mitochondrial genome. The mitochondrial genome sequence of the Yimeng scorpion enriches data resource for further research on genetic mechanism and classification.

Effects of ultrasound on the beef structure and water distribution during curing through protein degradation and modification.

The objective of this study was to explore the mechanisms of power ultrasound (PUS, 150 and 300W) and treatment time (30 and 120min) on the water-holding capacity (WHC) and tenderness of beef during curing. Beef muscle at 48h post mortem was subjected to PUS treatment at a frequency of 20kHz. Analysis of compression loss and shear force showed that PUS-assisted curing significantly increased the WHC and the tenderness of beef compared to static brining (p<0.05). According to the analysis of LF-NMR, PUS treatment could increase the P21 values which indicated an improvement in water-binding ability of beef muscle. SDS-PAGE and LC-ESI-MS/MS analysis suggested that PUS induced moderate oxidation of myosin causing polymerization, which may contribute to increased water retention. On the other hand, an increased tenderness of beef is suggested by the increased MFI values and proteolysis of desmin and troponin-T. Transmission electron microscopy (TEM) further supported the effects of PUS on WHC and tenderness changes due to the swelling and disruption of myofibrils. Thus, these results provide knowledge about the mechanism for improving WHC and tenderness of beef by PUS curing, which could be employed as an emerging technology for various meat curing processes.

Effects of power ultrasound on oxidation and structure of beef proteins during curing processing.

The aim of this study was to evaluate the effects of power ultrasound intensity (PUS, 2.39, 6.23, 11.32 and 20.96Wcm(-2)) and treatment time (30, 60, 90 and 120min) on the oxidation and structure of beef proteins during the brining procedure with 6% NaCl concentration. The investigation was conducted with an ultrasonic generator with the frequency of 20kHz and fresh beef at 48h after slaughter. Analysis of TBARS (Thiobarbituric acid reactive substances) contents showed that PUS treatment significantly increased the extent of lipid oxidation compared to static brining (P<0.05). As indicators of protein oxidation, the carbonyl contents were significantly affected by PUS (P<0.05). SDS-PAGE analysis showed that PUS treatment increased protein aggregation through disulfide cross-linking, indicated by the decreasing content of total sulfhydryl groups which would contribute to protein oxidation. In addition, changes in protein structure after PUS treatment are suggested by the increases in free sulfhydryl residues and protein surface hydrophobicity. Fourier transformed infrared spectroscopy (FTIR) provided further information about the changes in protein secondary structures with increases in ß-sheet and decreases in α-helix contents after PUS processing. These results indicate that PUS leads to changes in structures and oxidation of beef proteins caused by mechanical effects of cavitation and the resultant generation of free radicals.